The present invention relates to the field of mechanisms and methods for inserting and removing storage media cartridges from storage libraries.
User access to storage media cartridges inside a small automated storage library is typically accomplished through the front face of the storage library""s housing. This front access allows the storage library to be mounted in a standard rack or cabinet where the sides, top and bottom of the housing are hidden from the user. As such, there are tradeoffs in positioning of the storage media cartridges for accessibility by the human user and by the robotics. Early designs positioned all of the cartridges in a single row of cartridge slots positioned parallel to the front of the housing. The users directly inserted and removed these storage media cartridges in a horizontal plane through an opening in the exterior side of the cartridge slots. The robotics accessed the storage media cartridges horizontally through an opening in the interior side of the cartridge slots. This approach allowed for simple robotics while providing the user with access to all of the storage media cartridges held within the storage library.
Demands for increased capacity resulted in an increase in the number of storage media cartridges. Storage library designers started positioning some or all of the storage media cartridges away from the front face of the housing to keep the housing width within the nineteen-inch rack-mount requirement. As a result, the user could no longer directly access all of the storage media cartridges. Users had to rely on the robotics to transfer the storage media cartridges between a designated user accessible cartridge slot, or a special xe2x80x9cmailboxxe2x80x9d mechanism, and the other cartridge slots to insert new storage media cartridges into the storage library. The mailbox, or mail slot, is usually a specialized receptacle designed to rotate between two positions. In one position, an opening in the mail slot is positioned to face the user when manually receiving or dispensing one storage media cartridge. In the other position, the opening in the mail slot faces the robotic mechanism for automatic storage media cartridge insertion and removal. In contrast to the movable mail slot, the designated user accessible cartridge slot is typically stationary. The user accesses the slot through an external opening and the robotic mechanism accesses the slot through and internal opening.
Several mail slot mechanisms have been disclosed in U.S. Patents. For example, U.S. Pat. No. 5,894,367 issued to Rinard on Apr. 13, 1999, discloses a cylindrical-shaped mail slot that has a vertical opening for receiving the storage media cartridges. This mail slot is located between the front face of the storage library""s housing and a ring of cartridge slots that form the primary storage location inside the library. The mail slot rotates about a vertical axis between two positions. At the first, or user access position, the opening faces the user for manual storage media cartridge insertion and removal. At the second, or robot access position, the opening in the mail slot faces the robotic mechanism mounted in the interior of the storage library. At both positions, the storage media cartridge is moved in a horizontal plane during insertion and removal from the mail slot. Since the mail slot is outside the primary ring of cartridge slots, a gap must be left in the ring to allow the robotic mechanism to reach through to access the mail slot.
U.S. Pat. No. 5,454,485, issued to Dalziel on Oct. 3, 1995 discloses a mail slot that pivots about a horizontal axis. This mail slot is a five-sided receptacle with one open side for receiving a storage media cartridge. The mail slot is located between the front face of the storage library""s housing and a rotatable cylindrical carousel unit into which the cartridge slots are integrated. At the user access position, the mail slot extends at least partially out of the storage library""s housing and the opening is facing upward. The user inserts and removes storage media cartridges in a vertical plane. Vertical insertion and removal are preferred as compared with horizontal insertion and removal from a human factor point of view. At the robot access position, the mail slot extends at least partially inside the housing and the opening of the mail slot is facing sideways toward the robotic mechanism. Robotic insertion and removal of the storage media cartridges are done in a horizontal plane. A latch is included in the mail slot to hold the mail slot at the robot access position. To transfer a storage media cartridge between the carousel of cartridge slots and the mail slot, the carousel must be rotated to align the appropriate cartridge slot with the mail slot.
In both the Rinard and the Dalziel disclosures, the mail slot is a stand-alone mechanism physically separate from the main array of cartridge slots. Such designs add complexity to the storage library design since the robotic mechanism must have a physical range of motion to access the array of cartridge slots and the mail slot. The stand-alone mail slots also consume valuable real estate inside the housings. This is an important factor for small storage libraries where space is very limited.
U.S. Pat. No. 4,779,151 issued to Lind et al. on Oct. 18, 1988 discloses a mail slot mechanism integrated with the main array of cartridge slots. Like the mail slots described above, the mail slot disclosed by Lind is a five-sided receptacle with an open side for receiving the storage media cartridges. It also rotates about a vertical axis between a user access position and a robot access position. Insertion and removal of storage media cartridges from the mail slot are performed in a horizontal plane by both the user and the robotic mechanism. An important feature of this design is that when the mail slot is at the robot access position, the mail slot itself forms part of a column of cartridge slots. The robotic mechanism accesses the mail slot in the same fashion as the other cartridge slots in the column of cartridge slots.
The design disclosed by Lind has limitations from a human factor perspective. First the storage media cartridges are inserted and removed from the mail slot with a horizontal plane of motion. As mentioned earlier, a vertical plane of motion is preferred for the user. Second, a tradeoff is made between packaging density of the storage media cartridges and free space around the mail slot required by the user to grasp a storage media cartridge in the mail slot. Free space left above and below the mail slot for the sake of the user is space not used to hold other storage media cartridges. Positioning adjacent storage media cartridges close to the mail slot leaves less room for the user to grasp the storage media cartridge in the mail slot.
What is desired is a mail slot mechanism that is integral to the main array of cartridge slots. This feature allows for efficient positioning of the storage media cartridges and permits a simple robotic mechanism design. The mail slot should also be movable away from the main array of cartridge slots. This feature allows the user adequate free space around the storage media cartridge in the mail box to grasp and remove the cartridge. Finally, the mail slot should be oriented to allow for vertical or near vertical insertion and removal of the storage media cartridges.
The present invention is a mechanism and a method for inserting and removing storage media cartridges from a storage library having an array of cartridge slots. At least one cartridge slot of the array is a mail slot. The mail slot is pivotable between a first position and a second position. A spring normally biases the mail slot toward the first position. At the first position, the mail slot is a continuation of the array of cartridge slots. With the mail slot at the first position, a robotic mechanism inside the housing can insert and remove a storage media cartridge through a side opening in the mail slot. At the second position, the mail slot is tilted to face, or protrude through an opening in the storage library""s housing. Manual storage media cartridge insertion and removal from the mail slot are accomplished through a top opening in the mail slot with the mail slot in the second position.
In the preferred embodiment, the housing opening is covered by a door and the spring is disposed between the mail slot and the door. When the door is opened, the spring is decompressed and the mail slot pivots toward the second position. This provides the user with easy access to the mail slot. When the door is closed, the mail slot is pushed back into the array of cartridge slots. No motors, solenoids or actuators are required. In alternative embodiments, the spring may be disposed between the mail slot and the housing. In this case, the user must manually pull the mail slot to the second position.
A sensor may be included to detect when the mail slot is in the first position. Knowing when the mail slot is and is not at the first position is useful to the storage library""s electronics. When the mail slot is not at the first position, the robotic mechanism may be locked-out from accessing the mail slot. When the mail slot returns to the first position, the storage media cartridge in the mail slot may be audited to determine its identity.
Accordingly, it is an object of the present invention to provide a mail slot mechanism permitting insertion and removal of storage media cartridges from a storage library.
Another object of the present invention is to provide a storage library having a mail slot mechanism permitting insertion and removal of storage media cartridges from the main array of cartridge slots.
Yet another object of the present invention is to provide a method of operating the array of cartridge slots to receive and discharge the storage media cartridges from the storage library.
These and other objects, features and advantages will be readily apparent upon consideration of the following detailed description in conjunction with the accompanying drawings.